Answer:
The skinfold method, the measurement of subcutaneous fat folds, is the most widely adopted field method for the assessment of body fat, especially in children.
It is based on the principle that fat is of a known density and by “summing” measurements of subcutaneous fat thickness across the body, total and regional fat can be estimated.
Skinfold thickness measurements are typically used to rank individuals in terms of relative total “fatness”, or to assess subcutaneous fat at various regions of the body.
Population specific equations are used to derive estimates of percent body fat.
In infancy, it might be the sole tool available for assessing body composition longitudinally as other methods may not be feasible, or may only be suitable for use at body sizes e.g. PEA POD, can only measure infants up to 10kg.